AU729418B3

AU729418B3 - Cleaning of pipelines

Info

Publication number: AU729418B3
Application number: AU37826/00A
Authority: AU
Inventors: John William Harold Sly; Robert Harold Alexander Sly
Original assignee: Australian Ultra Violet Services Operations Pty Ltd
Current assignee: AUSTRALIAN ULTRA VIOLET SERVICES (OPERATIONS) Pty Ltd
Priority date: 1999-05-31
Filing date: 2000-05-31
Publication date: 2001-02-01
Anticipated expiration: 2006-05-31

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT

ORIGINAL

Applicant: AUSTRALIAN ULTRA VIOLET SERVICES (OPERATIONS) PTY LTD, ACN 007 292 257 Actual Inventor: John William Harold Sly and Robert Harold Alexander Sly Address for Service: PATENT ATTORNEY SERVICES 26 Ellingworth Parade Box Hill Victoria 3128 Australia Title: CLEANING OF PIPELINES The following statement is a full description of this invention, including the best method of performing it known to me/us:- CLEANING OF PIPELINES This invention relates to cleaning of pipelines such as potable water supply lines.

There is a known technique for cleaning pipelines such as potable water supply lines and sewage pipes known as "air scouring". This technique involves opening a valve such as a water hydrant provided at the downstream end of a section of pipeline to be cleaned so that water can flow through and discharge at a rapid rate from the discharge point. At a point upstream of the section of pipeline to be cleaned, air is compressed and injected under pressure into the pipeline in addition to water being supplied through the section of pipeline to be cleaned. In the case of a potable water supply pipeline, this water can be the normal flow of water that will occur upon opening of the valve at the downstream discharge point.

The injection of air under pressure into the flowing water causes considerable turbulence and substantially greater flow rate through the section of pipeline from the injection point to the discharge point and this causes a scouring action within the pipeline helping to dislodge and clean the section of pipeline of deposits including rust or other corrosion products, scale, deposited sediments, and plant growths algae) and/or colonies of microorganisms.

It is an object of the present invention to provide a method and apparatus for cleaning of pipelines which enables removal of undesired substances or deposits or accumulations within the pipeline and also provides a disinfecting action.

According to a first aspect of the present invention, there is provided a process for cleaning a pipeline by a flushing operation which includes: supplying a feed gas comprising pure oxygen or oxygen enriched gas to an ozone generator, generating ozone by processing the feed gas in the ozone generator, supplying the ozone containing gas from the ozone generator to a mixing stage where the ozone containing gas is mixed with water to create an ozone charged activated water, and supplying the ozone charged activated water under pressure to the pipeline to be cleaned and causing turbulent flow of ozone containing water through the pipeline to be cleaned.

The supply of gas charged water under pressure so that it flows through the pipeline in a turbulent manner produces a scouring action similar to that described above in relation to the known "air scouring" process.

However, the inclusion of ozone in the gas additionally produces a disinfecting action in the pipeline. Furthermore, the use of pure oxygen or oxygen enriched gas as the feed gas to the ozone generator enables production of a greater concentration of ozone in the activated water and furthermore augments the disinfection action by introduction of greater concentrations of molecular oxygen than air. Preferably the step of mixing the ozone containing gas with water to create the ozone charged activated water also includes production in the activated water of disinfecting agents selected from hydroxyl radicals and hydrogen peroxide. Hydroxyl radicals in significant concentrations can substantially augment the disinfecting action of the ozone, as can the oxidant hydrogen peroxide.

The references to "pure oxygen" above and this specification generally are to be understood as referring to generally available commercial grade oxygen and are not referring necessarily to laboratory or medical purity oxygen. The use of oxygen enriched gas as an alternative to pure oxygen includes oxygen enriched air and this may be produced for example by supplying air to the ozone generator in addition to oxygen from a suitable supply such as a stored oxygen cylinder or other pressure vessel.

In the preferred embodiment, the ozone containing gas is supplied from the ozone generator to the mixing stage at a pressure greater than the water into which the ozone containing gas is to be introduced and mixed so that the positive pressure differential assists the introduction and mixing of the gas into the water.

It is convenient to describe other aspects of the process according to the first aspect of the present invention in connection with apparatus for carrying out the process.

According to a second aspect of the present invention, there is provided an apparatus for cleaning a pipeline by a flushing operation, the apparatus including: feed means for supplying a feed gas comprising pure oxygen or an oxygen enriched gas, an ozone generator connected to receive the feed gas from the feed means and operatve to generate ozone in the feed gas, mixing means connected to receive ozone containing gas from the ozone generator and to mix the ozone containing gas with water therein to create ozone charged activated water, and supply means for supplying the ozone charged activated water from the mixing means to the pipeline to be cleaned under pressure to cause a turbulent flow of ozone containing water through the pipeline.

The ozone generator may comprise an irradiating device into which the feed gas is introduced and in which the formation of ozone is caused by the irradiation thereof The irradiating device may include an array of ultra-violet light sources for generating a flux of UV radiation of suitable wavelength to cause partial ionisation of molecular oxygen and formation of molecular ozone in the feed gas. In this embodiment, preferably the apparatus includes a cooling water flow path through which a cooling water flow is introduced into the irradiating device.

The mixing means may include a mixing line through which a flow of water is created and into which the ozone containing gas from the ozone generator is introduced to be mixed with the water therein. The ozone containing gas from the ozone generator may be under a positive pressure relative to the water pressure in the mixing line whereby mixing of the ozone containing gas with the water in the mixing line is promoted. Alternatively, or in addition, the mixing line may have a restriction therein at the region where the ozone containing gas from the ozone generator is introduced into the mixing line so that a venturi effect at the restriction promotes mixing of the ozone containing gas with the water flowing through the mixing line.

The apparatus may further include a main water line having an inlet which in use is connected to receive flow from the pipeline to be cleaned by the flushing operation and having an outlet for re-introducing the flow from the main water line back into the pipeline to be cleaned, the mixing line extending from an inlet tapping into the main water line and passing to a discharge tapping for re-introducing activated water back into the main water line. The section of the main water line from the inlet tapping of the mixing line to the discharge tapping of the mixing line preferably includes a bypass control valve which is selectively adjustable to enable control of the relative proportions of water flow which pass through the section of the main water line containing the bypass control valve and through the mixing line.

Possible and preferred features of the present invention will now be described with particular reference to the accompanying drawing. However it is to be understood that the features illustrated in and described with reference to the drawing are not to be construed as limiting on the scope of the invention. In the drawing: Fig. 1 is a schematic diagram of apparatus for cleaning a pipeline embodying the present invention.

The apparatus illustrated includes feed means 10 which includes one or more oxygen cylinders 11 such as commercial grade oxygen cylinders. The cylinders 11 supply the oxygen feed gas under pressure to the ozone generator 15. In the illustrated embodiment, the ozone generator 15 comprises an irradiating device 16 into which the oxygen feed gas is introduced and in which irradiation causes formation of ozone. The irradiating device may comprise for example an array of ultra violet light sources for generating a flux of UV radiation of suitable wave length to cause partial ionisation of the molecular oxygen and formation of molecular ozone in the feed gas. It will be appreciated, however, that other forms of ozone generator may be used, e.g. a device utilising electrical discharges to cause ozone formation.

Associated with the irradiating device 16 are appropriate electrical systems including for example a generator 17 and electrical control system 18 which in turn is electrically connected to the operative components of the irradiating device. Also as illustrated, cooling water flow can be introduced into the irradiation device 16 through cooling water inlet line and the cooling water outlet line 21 can carry the discharged cooling water to a waste discharge point.

The ozone containing gas produced in the ozone generator 15 passes from outlet 22 under pressure to the mixing stage 25 where the ozone containing gas is mixed with water to create ozone charged activated water. As discussed earlier, the activated water can also include further disinfecting oxidants particularly hydroxyl radicals (and possibly hydrogen peroxide) as a result of the introduction of the ozone containing gas into the water in the mixing stage 25 so that the ozone and hydroxyl radicals are present in significant concentrations in the activated water in the mixing line 26. Because the ozone containing gas from the ozone generator 15 is under a positive pressure relative to the water pressure in mixing line 26, the mixing of the gas into the water is promoted and can occur continuously as the water flows through the mixing line 26. Alternatively, or in addition, a venturi (not shown) can be provided in the mixing stage 25 to enable or to assist mixing of the ozone containing gas in the water.

The water passing through the mixing line 26 comes from a supply means 29 including the main water line 30. This line 30 has an inlet 31 into which water from the pipeline to be cleaned, for example, can be introduced. A water sample point 32 can be provided in the vicinity of the inlet 31 and an inlet control valve 33 is provided for selectively closing off the water flow through the line 30. It will be seen that the line 20 for the cooling water supplied to the ozone generator 15 also taps into the main water line The mixing line 26 draws water from the main water line 30 at inlet tapping 27 and returns activated water charged with ozone at discharge tapping 28. However, the main water line 30 also has a section 35 in parallel with the mixing line 26. The section includes a bypass control valve 36 which can enable selective adjustment of 'the relative proportions of the water flow which pass through the section 35 and through the mixing line 26. Downstream of the mixing stage 25, the main water line 30 passes to an outlet control valve 37 which, like the inlet control valve 33, enables closing of the main water line Adjacent the outlet 39 of the main water line 30 there is an outlet water sample point 38.

The use of the apparatus described and illustrated in the drawing should be readily understandable from the preceding description in the drawing itself The apparatus in use can be provided as a mobile pipeline cleaning system, e.g. provided on a trailer or motor vehicle so that the apparatus can be moved to the site of the section of pipeline to be cleaned.

Water from the pipeline to be cleaned can be coupled to the inlet 31 and the outlet 39 can be coupled to the pipeline so as to flow into the section to be cleaned. Valves 33 and 37 can be opened and a water discharge or release point downstream of the pipeline section to be cleaned can be fully opened. Water flows from the pipeline upstream of the section to be cleaned and to the inlet 31, through the main water line 30 of the apparatus through outlet 39, and through the section of pipeline to be cleaned to be finally discharged from the opened discharge point. The ozone generator 15 can be operated to create ozone using the pure oxygen or oxygen enriched air and the ozone containing gas is supplied under pressure to the mixing stage 25 where it will mix with water flowing through the mixing line 26 creating a turbulent mix of ozone charged activated water downstream of the mixing stage. The ozone, molecular oxygen and expected hydroxyl radicals will produce a disinfecting action through the pipeline to be cleaned.

It will be understood that variations and alterations of the non-essential features of the present invention are possible. For example, the apparatus could be used in association with a generally conventional air scouring system in which compressed air is introduced under pressure into the section of pipeline to be cleaned. The introduction of ozone charged activated water to disinfect the line can be carried out simultaneously with the air scouring operation or can be carried out after a conventional air scouring operation to disinfect the line which has been newly "physically" cleaned by the air scouring process.

It is to be understood that various alterations, modifications and/or additions may be made to the features of the possible and preferred embodiment(s) of the invention as herein described without departing from the spirit and scope of the invention as defined in the following claims.

Claims

1. A process for cleaning a pipeline by a flushing operation which includes: supplying a feed gas comprising pure oxygen or oxygen enriched gas to an ozone generator, generating ozone by processing the feed gas in the ozone generator, supplying the ozone containing gas from the ozone generator to a mixing stage where the ozone containing gas is mixed with water to create an ozone charged activated water, and supplying the ozone charged activated water under pressure to the pipeline to be cleaned and causing turbulent flow of ozone containing water through the pipeline to be cleaned.

2. A process as claimed in claim 1 wherein the ozone containing gas from the ozone generator is supplied to the mixing stage at a pressure greater than the water into which it is mixed so as to thereby promote the introduction and mixing of the gas into the water.

3. A method as claimed in claim 1 or 2 wherein the step of mixing the ozone containing gas with water to create the activated water includes passing a flow of water through a mixing line into which the ozone containing gas from the ozone generator is introduced to be mixed with the water therein, the method further including passing a main water flow through a main water line having an inlet which is connected to receive flow from the pipeline being cleaned by the flushing operation and having an outlet re-introducing the flow from the main water line back into the pipeline being cleaned, the mixing line extending from an inlet tapping into the main water line and passing to a discharge tapping re-introducing activated water back into the main water line. Dated this 31st day of May 2000 PATENT ATTORNEY SERVICES Attorneys for AUSTRALIAN ULTRA VIOLET SERVICES (OPERATIONS) PTY LTD